The study involves 10 sessions (in addition to the screening visit) over 3 months. Sessions 1-5 are completed over 5 consecutive days. Sessions 6-10 are divided over the remaining time. Participants are randomly assigned to one of three groups: 1) tDCS during motor training; 2) tDCS after training; or 3) training with sham tDCS. During these sessions, participants perform a pinch force task (squeezing a small device between the thumb and forefinger) and visuomotor tasks (using a device to move the cursor on a computer screen to various targets and holding the cursor in place for 1 second).